Two pro-Palestinian activists who were raised in the United States, and who were on board the main ship in the flotilla challenging Israel’s naval blockade of Gaza last week when it was raided by Israeli commandos, have denied a claim by Israel’s military that they are “involved in terrorist activity.”

Fatima Mohammadi, an American lawyer from Chicago, and Ken O’Keefe, a former American marine, were both on a list of “Active Terror Operatives,” posted on the official blog of the Israel Defense Forces on Sunday. The I.D.F. statement, which named five passengers on board the Mavi Marmara “known to be involved in terrorist activity,” included factual errors about both Ms. Mohammadi and Mr. O’Keefe.

The Israeli statement misspelled Ms. Mohammadi’s first and last names, calling her “Fatimah Mahmadi”; said she is “an active member of the organization ‘Viva Palestine’ ” — she is a former employee of Viva Palestina; and called her “a United States resident of Iranian origin.” She is an American citizen who was born in Tehran in 1979 and moved — with her American mother and Iranian father — to Boise, Idaho, after the Iranian revolution that year.

In an e-mail interview on Tuesday, Ms. Mohammadi — whose Facebook page lists “Rabble Rousing” under “Activities” — told The Lede that the Israeli authorities made no such claims to her while she was in their custody, “though they were very interested in the fact that I was born in Iran.” She added:

I saw the statement on Sunday afternoon after I arrived in the U.S. and I was shocked. On one hand, it’s incredibly comical because it’s so illegitimate and unfounded, but on the other hand, I am angered that they would attempt to discredit humanitarian aid workers in such a fear-based manner.

The Israeli statement also claimed that Ms. Mohammadi “attempted to smuggle forbidden electronic components into the Gaza Strip.” Ms. Mohammadi said:

I have no idea what they’re referring to as the only electronics I had in my possession or in my bag were personal items: a camera, a video camera, and my personal phones. All electronics, including laptops, were confiscated at our arrest while on board the ship and none have been returned. Any cameras that did make their way to Turkey were either smashed or, at the very least, stripped of their memory cards.

She also said that she witnessed the deadly commando raid on the ship:

I was on the top deck (fifth deck) when the shooting began and stayed up until a cameraman about 2 meters away from me was shot twice in the arm. After I took him to the medical deck and helped there, I scurried between the second, third and fourth decks, slipping on blood all the way. Most of my time was spent on the medical deck, however, tending to the victims of the massacre. Two men died in front of me.

The I.D.F. statement called the other activist, Ken O’Keefe, “an American and British citizen.” The Irish Times reported on Tuesday: “Mr. O’Keefe, who lives in London, has carried an Irish passport since 2003 due to his grandmother, from Listowel, Co. Kerry. He has never taken British citizenship and says he renounced his U.S. citizenship in 2001.”

Mr. O’Keefe is well-known in Britain for his antiwar activism. In 2003, he appeared on the BBC to explain why he had volunteered to serve as a human shield in Iraq to try to prevent an American attack.

On Tuesday, The Times of London explained:

The words inked into the right hand of the 1991 Gulf War veteran — “U.S. Expatriot, 01-03-01, R.I.P.” — mark the date that he renounced his U.S. citizenship after what he called a taste of military injustice. Mr. O’Keefe said that he was subjected to institutional bullying in the U.S. Marine Corps after he went over the head of his commanding officer to report an unspecified infraction.

The Israeli military’s statement said that he is “a radical anti-Israel activist and operative of the Hamas Terror organization. He attempted to enter the Gaza Strip in order to form and train a commando unit for the Palestinian terror organization.”

Mr. O’Keefe angrily denied these charges in an interview with Al Jazeera.

The Israeli newspaper Yedioth Ahronoth’s Ynet News Web site reported on Monday that Mr. O’Keefe told Hurryiet, a Turkish newspaper, that he had helped to capture two of the commandos as soon as they landed on the ship. He said, “The lives of the three commandos were at our mercy — we could have done with them whatever we wanted.” He also said he had helped to disarm one of the commandos: “I took one of their guns, and another activist grabbed him. He had a 9mm gun. We didn’t use the weapons against the Israeli soldiers. I unloaded the magazine and took out the bullets — we didn’t come here to fight.”

Eventually, he added, the activists decided to release the soldiers unharmed. “They looked at us, and thought we were about to kill them, but then we let them go,” he said.

Mr. O’Keefe later gave Ynet a longer account of the raid in an interview with the Israeli newspaper.